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Broadband strong optical dichroism in topological Dirac semimetals with Fermi velocity anisotropy

Chinese Physics B 2020年第7期29卷 128-134页

作者： j Lim K j A Ooi C Zhang L K ang Yee Sin ang Science Math and TechnologySingapore University of Technology and DesignSingapore School of Energy and Chemical Engineering Xiamen University MalaysiaSelangor Darul Ehsan 43900Malaysia College of Chemistry and Chemical Engineering Xiamen UniversityXiamen 361005China School of Physics University of WollongongNorthfields AvenueNew South Wales 2522Australia

Prototypical three-dimensional(3D)topological Dirac semimetals(DSMs),such as Cd3As2 and Na3Bi,contain electrons that obey a linear momentum-energy dispersion with different Fermi velocities along the three orthogonal momentum *** being extensively studied in recent years,the inherent Fermi velocity anisotropy has often been neglected in the theoretical and numerical studies of 3D *** this omission does not qualitatively alter the physics of light-driven massless quasiparticles in 3D DSMs,it does quantitatively change the optical coefficients which can lead to nontrivial implications in terms of nanophotonics and plasmonics *** we study the linear optical response of 3D DSMs for general Fermi velocity values along each *** the signature conductivity-frequency scaling,σ(ω)∝ω,of 3D Dirac fermion is well-protected from the Fermi velocity anisotropy,the linear optical response exhibits strong linear dichroism as captured by the universal extinction ratio scaling law,Λi j=(vi/v j)^2(where i=j denotes the three spatial coordinates x,y,z,and vi is the i-direction Fermi velocity),which is independent of frequency,temperature,doping,and carrier scattering *** Cd3As2 and Na3Bi3,an exceptionally strong extinction ratio larger than 15 and covering a broad terahertz window is *** findings shed new light on the role of Fermi velocity anisotropy in the optical response of Dirac semimetals and open up novel polarization-sensitive functionalities,such as photodetection and light modulation.

关键词： topological Dirac semimetal optical anisotropy linear dichroismn linear response theory

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数字经济、创新能力与经济高质量发展

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江苏商论 2025年第1期 22-27,36页

作者：臧守芳盐城师范学院数学与统计学院盐城数字经济研究院数字金融研究所江苏盐城224002

当前,中国经济已经由高速发展转向高质量发展,数字经济作为经济发展的新动能,正成为推动经济高质量发展的重要引擎。文章基于2011—2019年省级面板数据,通过构建综合评价指标体系,利用固定效应模型,从创新视角出发,探究数字经济影响高... 详细信息

当前,中国经济已经由高速发展转向高质量发展,数字经济作为经济发展的新动能,正成为推动经济高质量发展的重要引擎。文章基于2011—2019年省级面板数据,通过构建综合评价指标体系,利用固定效应模型,从创新视角出发,探究数字经济影响高质量发展的内在机制。结果表明,数字经济有效推动了经济高质量发展;创新能力在其中发挥了正向调节作用。这种影响作用存在区域异质性,中西部地区相较于东部地区更为明显。因此,文章提出了加强科技创新,持续推进数字产业化和产业数字化建设,施行差异化数字转型策略,并加强风险防范的建议。

关键词：创新能力数字经济高质量发展

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Daily high-dose aspirin does not lower APRI in the Aspirin-Myocardial Infarction Study

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The journal of Biomedical Research 2020年第2期34卷 139-142页

作者： Shilpa Tiwari-Heckler zgordon j.ang Yury Popov Kenneth j.Mukamal Division of Gastroenterology and Hepatology Department of MedicineHarvard Medical SchoolBostonMA 02115USA Division of General Medicine Beth Israel Deaconess Medical CenterHarvard Medical SchoolBostonMA 02115USA

Antiplatelet agents reduce liver fibrosis by inhibiting platelet activation and platelet-derived growth factor production. Previous cross-sectional epidemiological studies suggest that the use of aspirin is related to reduced liver fibrosis. The Aspirin-Myocardial Infarction Study(AMIS) aims to examine this relationship in a multicenter,randomized, double-blind and placebo-controlled trial. The existing clinical trial of aspirin was conducted to study the benefit of one gram aspirin daily among 4 524 individuals who had experienced at least one documented myocardial infarction. The aspartate aminotransferase(AST)-to-Platelet Ratio Index(APRI) was calculated at baseline and annually from the platelet count and AST levels. Participants in the AMIS trial had a mean baseline APRI of 0.34±0.36, and only 1% individuals had APRI scores higher than 1.0, a common cutoff for cirrhosis. The daily use of aspirin was associated with an increase, rather than a reduction of APRI, by 0.007 per year(95% CI0.002-0.015, P=0.12). The use of aspirin did not significantly affect platelet counts. In a sensitivity analysis of individuals with probable significant fibrosis at baseline(APRI≥0.7), the aspirin group had a sustained reduction in APRI over time, although this change was not significant compared to that in the placebo group. In the AMIS trial, the daily use of high-dose aspirin did not significantly affect APRI, a surrogate index of liver fibrosis. This study highlights the need for de novo clinical trials to investigate the potential benefit of antiplatelet agents on liver fibrosis.

关键词： liver fibrosis aspirin APRI antiplatelet AMIS

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Motor skills matter to physical activity——At least for children

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journal of Sport and Health Science 2013年第1期2卷 58-59页

作者： ang Chen Department of Kinesiology University of North Carolina at GreensboroGreensboroNC 27412USA

Physical activity(PA) is an effective means of curbing the prevalence of child obesity,and fundamental skills are hypothesized to be an important factor that determines physically active or inactive behavior in *** evidence suggests that adolescents and young adults with proficient motor skills in sport-related activities are more likely to have a physically active lifestyle.1 Because

关键词：学龄前儿童运动体力预测能力生活方式成年人患病率肥胖症

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Exercise facilitates memory:Implications for helping youngsters learn in school

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journal of Sport and Health Science 2012年第1期1卷 5-6页

作者： ang Chen Department of Kinesiology School of Health and Human SciencesUniversity of North Carolina at GreensboroGreensboroNorth Carolina 27412USA

Up to this day I still can vividly remember a routine in my elementary school:the daily school-wide morning calisthenics. It started at about 7:45 am in the school *** physical education teacher stood on the concrete stage where our principal would give her talk at school *** children and teachers would follow the teacher’s lead to do the eight-segment national calisthenics in unison with loud music from loudspeakers affixed on trees around the *** I visited the school last May,I saw that students still performed the routine faithfully but with a different set of

关键词： helping routine remember morning visited elementar

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Hollow spherical titanium dioxide nanoparticles for energy and environmental applications

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Particuology 2015年第5期13卷 13-23页

作者： Peng Zhang ang Li jinlong Gong Key Laboratory for Green Chemical Technology of Ministry of Education School of Chemical Engineering and TechnologyTianjin UniversityCollaborative Innovation Center of Chemical Science and Engineering

Hollow spherical titanium dioxide （TiO2） nanoparticles possess unique properties toward energy and environmental applications, because of the intrinsic properties of TiO2 and benefits induced by their hollow structure. A detailed understanding of TiO2 hollow spheres will promote their use in sustainable energy and environmental applications. This perspective details current methods for synthesizing hollow spherical TiO2 nanoparticles, and their performance in dye-sensitized solar cells, photocatalysts, and batteries. This perspective will promote the design and innovative thinking on the application of hollow spherical metal oxide nanooarticles.

关键词： TiO2 Hollow sphere Dye-sensitized solar cell Photocatalyst Battery

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Collision risk assessment of reduced aircraft separation minima in procedural airspace using advanced communication and navigation

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Chinese journal of Aeronautics 2023年第4期36卷 315-337页

作者： Qing CAI Hao jie ang Sameer ALAM Air Traffic Management Research Institute School of Mechanical&Aerospace EngineeringNanyang Technological University639798Singapore

With the advancement of Communication,Navigation and Surveillance(CNS)technolo-gies such as space-based Automatic Dependent Surveillance-Broadcast/Contract(ADS-B/C),large separation minima may be reduced in procedural *** is of great significance to know the upper limit of the Reduced Separation Minima(RSM)for a procedural airspace and the corre-sponding consequences on collision risk with specifics of the advanced ADS-B and control interven-tion *** this work,an interactive software is first developed for collision risk *** software integrates the International Civil Aviation Organization(ICAO)collision risk models for lateral and longitudinal collision risk calculation for the Singapore procedural *** demonstrate that the lateral and longitudinal collision risk of Singapore procedural airspace with respect to current control procedures meets the ICAO Target Level of Safety(TLS)***,the feasibility of reducing the horizontal separations implemented in the Singapore pro-cedural airspace with respect to advanced CNS techniques is *** is found that if advanced CNS technologies are applied,then the current 50-NM lateral and longitudinal separa-tion standards can be reduced to 22 NM(1 NM=1.825 km)and 20 NM,respectively,to meet the TLS standards based on current demand.A method is then devised to expand the traffic demand by p for p∈[10%,200%].It is found that the minimum lateral and longitudinal separa-tions can be reduced from 50 NM to be within the range of[23,31]NM,and 20 NM,respectively,for p∈[10%,200%],while the collision risk still meets the TLS standards.

关键词： Air transportation Collision risk Procedural airspace Separation minima Space-based Automatic Dependent Surveillance-Bro adcast/Contract(ADS-B/C)

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A clash of fundamental assumptions:Can/should we measure physical literacy?

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journal of Sport and Health Science 2020年第2期9卷 149-151页

作者： ang Chen Department of Kinesiology University of North Carolina at GreensboroGreensboroNC 27412USA

The special issue of the journal of Teaching in Physical Education (jTPE)~1 on physical literacy (PL) has provided much needed information about measuring and assessing student learning in terms of the well-defined and yet abstract *** authors have elaborated from diverse educational and psychometric perspectives on the development of the construct,the measurement model,and the assessment of the *** this attempt,many issues associated with the conception of PL were clarified and insightful information and arguments were brought *** this regard,the special issue has moved our understanding of the concept one step *** importantly,it points to a possibility to actualize the teaching of the concept in physical education (PE).

关键词： has clarified insight

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Theoretical analysis of influencing factors on resistance in the process of gas migration in coal seams

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International journal of Mining Science and Technology 2017年第2期27卷 315-319页

作者： Wang Kai Liu ang Zhou Aitao School of Resource and Safety Engineering China University of Mining and Technology State Key Laboratory of Coal Resource and Mine Safety School of Resources and Safety Engineering

Inspired by previous resistance models for porous media, a resistance expression of gas migration within coal seams based on the ideal matchstick geometry, combined with the Darcy equation and the modified Poiseuille equation is proposed. The resistance to gas migration is generally dynamic because of the variations in adsorption swelling and matrix shrinkage. Due to the limitations of experimental conditions,only a theoretical expression of resistance to gas migration in coal is deduced, and the impacts of tortuosity, effective stress and pore pressure on the resistance are then considered. To validate the proposed expression, previous data from other researchers are adopted for the history matching exercise, and the agreement between the two is good.

关键词： Porous media Gas Resistance Tortuosity Effective stress Pore pressure

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Understanding yields in alley cropping maize (Zea mays L.) and Cassia siamea Lam. under semi-arid conditions in Machakos, Eastern Kenya

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journal of Environmental Sciences 2001年第3期13卷 291-298页

作者： DNMungai CjStigter CLCoulson jKNg’ang’A GWSNetondo GOUmaya TTMI Project University of NairobiP.O.Box 30197NairobiKenya Department of Geography Department of Botany Department of Meteorology TTMI-Project Department of Environmental SciencesCT.de Wit Graduate School of Production Ecology and Resource ConservationWageningen UniversityDuivendaal 26701 AP WageningenThe Netherlands.

Six seasons of experiments in Machakos, Kenya, revealed that above about 150 mm of rainfall, maize yields per row in alley cropped “replacement” agroforestry (AF) plots, of Cassia siamea Lam. and maize ( Zea mays, cv. Katumani Composite B), may be expected to exceed those in the control (sole maize) plots. Such yields were insufficient to compensate for the area “lost” to the hedgerows. Below about 150 mm the control plots may be expected to perform better. This result was due to competition for water. Greater association of the fine roots of Cassia and maize was observed in the middle of the alleys than near the hedgerows. Photosynthetic consequences of shading were insignificant relative to other factors. In the alleys, reductions of soil temperature due to shade in the western and eastern maize rows were higher than in the middle row. Soil moisture extraction was higher in the AF than in the control plots. In the AF plots, moisture extraction was greater under the central maize rows than under those nearest the Cassia. Yield patterns followed such soil temperature and soil moisture patterns. Maize transpiration and photosynthetic rates were significantly higher in the control than in the AF plots during a below average rainy season but not during above average rainy seasons. It is concluded that alley cropping under semi arid conditions should be approached differently from the system worked on. It must at least provide strong physical protection of crops and/or soils and have a strong economic incentive to be of interest to the farmers.

关键词： alley cropping Cassia siamea competition Kenya maize yields microclimate mulching semi arid conditions

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